This invention relates to boring machines, and in particular, to an improved thrust system for a horizontal directional drill.
Horizontal directional drills are portable drilling rigs or boring machines which are smaller and lighter in comparison to their vertical counterparts. These types of drills are particularly suited for the installation of small diameter, underground utility service. Previously, the installation of such utility service was accomplished by trench digging equipment or the like. The use of trench digging equipment to install such service is time consuming, inefficient and expensive. As such, alternate devices, such as horizontal directional drills, which are simple and inexpensive to operate are highly desirable.
While prior horizontal directional drills are adequate for certain applications, such types of drills have been limited by the amount of thrust and pullback of the drill at given torques. Consequently, it is highly desirable to provide a horizontal directional drill with more thrust and pullback of the drill at given torques to overcome the deficiencies in the prior.
Therefore, the primary object and feature of the present invention to provide a horizontal directional drill having a thrust system which generates greater thrust and pullback at a given torque.
It is a still further object and feature of the present invention to provide a horizontal directional drill having a thrust system which is simple to construct.
It is a still further object and feature of the present invention to provide a horizontal directional drill which is portable and may be repositioned easily.
In accordance with the present invention, a horizontal directional drill having an improved thrust system is provided. The thrust system includes a drill boom extending along a longitudinal axis and terminating at first and second opposite ends. A drive sprocket is positioned at the first end of the drill boom and a driven sprocket is positioned at the second, opposite end of the drill boom. A carriage is supported by the drill boom for movement therealong. The carriage has a first and second idler sprockets positioned between the drive sprocket and the driven sprocket in the drill boom. A chain is also positioned within the drill boom and has first and second ends fixed therein. The chain extends about the drive sprocket, the driven sprocket and the idler sprockets such that rotation of the drive sprocket in a first direction drives the carriage toward a first end of the boom, and rotation of the driven sprocket in a second direction draws the carriage toward a second end of the drill boom.
The thrust system further includes a drive mechanism for rotating the drive sprocket in the first and second directions. It is contemplated that the drive mechanism include a hydraulic motor.
The drill boom includes one or more guide tracks extending along the longitudinal length thereof. The carriage includes a corresponding number of guiding members which engage corresponding guide tracks and guide the longitudinal movement of the carriage. The chain successively engage the first idler sprocket, the drive sprocket, the driven sprocket and the second idler sprocket. The first end of the chain is affixed adjacent to the drive sprocket and the second end of the chain is affixed adjacent the driven sprocket. A chain tension adjustment mechanism is interconnected to the driven sprocket for adjusting the tension on the chain.
In accordance with a still further aspect of the present invention, a thrust system for a horizontal directional drill is provided. The thrust system includes a drill boom extending along a longitudinal axis and terminating at first and second opposite ends. The drill boom includes a rotatable drive sprocket positioned at the first end of the drill boom and a rotatable driven sprocket positioned at the second end of the drill boom. A carriage supports the drill and is movable along the drill boom. The carriage includes first and second idler sprockets positioned between the drive sprocket and the driven sprocket in the drill boom. Guide structure guides the movement of the carriage along the drill boom. A chain having first and second ends affixed within the drill boom extends about the drive sprocket, the driven sprocket, and the idler sprocket, such that rotation of the drive sprocket in a first direction draws the carriage towards the first end of the drill boom and rotation of the drive sprocket in a second direction draws the carriage toward the second end of the drill boom. A drive mechanism is provided for rotating a drive sprocket in a predetermined direction.
The guide structure includes first and second guide tracks extending along the length of the drill boom, and first and second guiding members extending from the carriage. Each guiding member engages a corresponding guide track.
In accordance with a still further aspect of the present invention, a thrust system for a horizontal directional drill is provided. The thrust system includes a drill boom extending along a longitudinal axis and terminating at first and second opposite ends. The drill boom includes a rotatable drive sprocket positioned at the first end of the drill boom and a rotatable driven sprocket positioned at the second end of the drill boom. First and second guide tracks extend along the length of of the drill boom. A carriage is provided for supporting the drill. The carriage is movable along the drill boom and has first and second idler sprockets positioned between the drive sprocket and the driven sprocket between the drill boom. First and second guiding members extend from the carriage. Each guiding member engages a corresponding guide track for guiding movement of the carriage along the drill boom.
A chain having first and second ends fixed within the drill boom is provided. The chain extends about the drive sprocket, the driven sprocket and the idler sprockets, such that rotation of the drive sprocket in a first direction draws the carriage toward the first end of the drill boom, and rotation of the drive sprocket in a second direction draws the carriage towards the second end of the drill boom. A drive mechanism is provided for rotating the drive sprocket in a predetermined direction.
A chain tension adjustment mechanism may be interconnected to the driven sprocket for adjusting the tension of the chain.